1. Field of the Invention
This invention relates to the field of water sports equipment and, in particular, relates to an improved swimming flipper of the type worn on the feet of swimmers, surfers and divers.
2. State of the Prior Art
Swimming flippers, also called swim fins, have been long used by water sports enthusiasts as a swimming aid to augment the (effective area of the swimmer's foot and increase the propulsive power developed by kicking motions in the water. Swimming flippers of this type typically include a shoe portion or foot pocket which defines a foot receiving cavity, and a wide, generally triangular blade fixed to the foot pocket at its narrow end, the wide end of the blade lying forward of the foot pocket. The foot pocket usually admits only the forward portion of the foot and a heel strap secures the flipper on the foot. Flippers are molded of rubber or other flexible rubber-like synthetic material.
Swimming flippers push large volumes of water and reduce the effort required of the swimmer for rapid forward motion through the water. The efficiency of a particular flipper depends on its design. The wide flipper blade flexes as it is pushed back and forth by the foot against resistance of the water. Such flexing diminishes the propulsive efficiency of the blade and consequently relatively stiff but pliable materials must be used in its manufacture. However, opposite considerations apply to the foot pocket portion of the flipper, which should be relatively soft and pliable for optimum comfort of the foot and to avoid chafing, bruising or blistering of the skin. A compromise, therefore, must be achieved in the selection of materials to satisfy these conflicting objectives. Flipper efficiency is also degraded by lateral water flow over the side edges of the flipper blade, which diminishes the volume of water displaced by the blade as it pushes through the water.
Yet another shortcoming of existing swimming flippers is that they are often lost when the heel strap slips off or the flipper is knocked off the foot, for example when a body surfer tumbles in breaking surf.
A continuing need exists for an improved swimming flipper which can be made at relatively low cost without sacrifice in performance.